Page:Smithsonian Miscellaneous Collections, Volume 85.djvu/98

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 * Aysheaia pedunculata Walcott, 1911, Smithsonian Misc. Coll., vol. 57, p. 117, pl. 23, figs. 8-9.
 * Aysheaia pedunculata Hutchinson, 1930, Proc. U. S. Nat. Mus., vol. 78, art. 11, p. 14.

This fossil has perhaps attracted wider attention than any other. Recently G. E. Hutchinson, of Yale University, studied this peculiar form and concluded that Aysheaia is an extinct Onychophora. Unfortunately, Mr. Hutchinson did not see the two individuals here illustrated, as they were buried away among numerous specimens of Ottoia. As the present assemblage of material progressed they came to light and are now illustrated, especially as they are perhaps the best preserved specimens available.

At the time these photographs were found among the notes Doctor Walcott intended using in further publications relating to this animal, two letters were discovered, both suggesting that Aysheaia may be an Onychophora or a Peripatus. The first letter, dated September 21, 1911, was written by Prof. W. M. Wheeler of Harvard University, and reads as follows:

"I wish to thank you for your very interesting publications on the Middle Cambrian Annelids. On plate 22, I noticed two figures of Aysheaia pedunculata. This creature bears the most extraordinary resemblance to Peripatus, except for the head, and judging from the figures the 'head' may be something which does not belong to the fossil. I have just shown these figures to Mr. C. T. Brues, who has been working on Peripatus, and he also was struck with the remarkable resemblance. Is there any possibility that it might be Peripatus instead of an Annelid? If this should prove to be the case it would be a matter of the very greatest interest."

The second letter dated October 25, 1911, was written by Prof. Charles Schuchert, of Yale University, and contains the following:

"The other point is one that Lull has called my attention to and refers to figures 8 and 9 of plate 23 which you call Aysheaia pedunculata. The question that I want to ask is, have you considered it as a possible Onychophora or related to Peripatus? Of course if one looks at your illustrations and compares them with the illustration of Peripatus given by Parker and Haswell in their Text-book of Zoology, page 607, in the edition of 1910, one can see considerable differences and yet there are in your figures several points in common to make one wonder whether you have not a marine ancestor of this land-living arthropod."

This rather lengthy historical account is presented to show that at least three authorities arrived at the same conclusions independently.

Plesiotypes.—U. S. N. M., Nos. 83942a-b.


 * Leanchoilia superlata Walcott, 1912, Smithsonian Misc. Coll., vol. 57, p. 170, pl. 31, fig. 6.

Original description.—"Body elongate, with clearly defined head shield and nine strong body segments up to the point where the